/*
Problem Description
There are some students in a class, Can you help teacher find the highest student .
Input
There are some cases. The first line contains an integer t, indicate the cases; Each case have an integer n ( 1 ≤ n ≤ 100 ) , followed n students’ height.
Output
For each case output the highest height, the height to two decimal plases;
Sample Input
2
3 170.00 165.00 180.00
4 165.00 182.00 172.00 160.00
Sample Output
180.00
182.00
 */
package com.yuan.algorithms.training20150721;

import java.util.Scanner;

public class 最高的学生 {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		double max = -0xffffff;;
		while(sc.hasNext()) {
			int t = sc.nextInt();
			while(--t>=0) {
				int n = sc.nextInt();
				max = -0xffffff;
				while(--n>=0) {
					double a = sc.nextDouble();
					if (a>max) {
						max = a;
					}
				}
				System.out.printf("%.2f", max);
				System.out.println();
			}
		}
	}

}
